Breath alcohol-measuring devices are known to be used in the area of traffic checks by the police or also to test employees within companies in order to check alcohol abuse and especially to eliminate work-related or industrial accidents due to the influence of alcohol. The principle of measurement has proved itself and is based, in general, on an electrochemical measurement or on the measurement of the infrared optical absorption.
In addition, there have been so-called Interlock® devices for some years now, i.e., vehicle immobilizers especially in motor vehicles, which are combined with a breath alcohol-measuring device. These are used to prevent a driver who is under the influence of alcohol from starting up the motor vehicle in question.
The risk of manipulation is a problem in the case of the prior-art combinations of vehicle immobilizers and breath alcohol-measuring devices because the breath samples for the breath alcohol measurement may be given by persons other than the authorized driver.